JPH0647509B2 - Solid electrolyte conductor and method for producing the same - Google Patents

Description

The present invention relates to a solid electrolyte conductor and a method for manufacturing the same.

According to the invention, a method for producing a surface of a ceramic solid electrolyte conductor containing alkali metal ions in the molten state by means of an alkali metal whose ions are conducted through the ceramic so as to improve the wettability of said surface. There
Wetting the ceramic surface with a solution of a transition metal salt liquid solvent, drying the surface, and evaporating the solvent to leave a salt deposit on the surface, converting the deposited salt to a transition metal oxide. By providing a surface of a solid electrolyte conductor comprising fixing a transition metal oxide to the surface, by providing a surface of a ceramic solid electrolyte conductor containing alkali metal ions, wetting the surface. A method of making a molten alkali metal whose ions are conducted through a ceramic so as to improve its properties by wetting a ceramic surface with a suspension of a transition metal oxide and drying said surface. And fixing the oxide to the surface by evaporating the suspension to leave a deposit of oxide on the surface and heating the dried surface. Manufacturing method is provided.

Here, “fixing” in “fixing the transition metal oxide on the surface of the ceramic solid electrolyte conductor” means so-called “doping”.

In addition, according to the present invention, the alkali metal ion having a surface on which a deposit of a transition metal oxide is provided so as to improve the wettability by the molten alkali metal to which the ion is conducted, is included. A separator that is provided with a ceramic solid electrolyte conductor and that is a ceramic solid electrolyte conductor containing a molten alkali metal anode, a cathode, and an anode alkali metal ion between and spaced from each other. A high temperature electrochemical storage cell having a separator having a surface in contact with the molten anode metal of the anode,
The surface is provided with a ceramic solid electrolyte conductor on which the molten alkali metal of the anode is provided with a deposit of a transition metal oxide to improve its wettability.

Although the method described above includes doping the ceramic surface with an oxide of any transition metal, or a mixture of any one or more transition metal oxides, the present method conveniently does not provide a single ceramic surface. Doping with one transition metal oxide is common.

Accordingly, the main application of the present invention is the doping of ceramic solid electrolyte conductors containing alkali metal ions for use in high temperature electrochemical cells, the molten alkali metal of which the ions are conducted through the ceramic. An anode is included in the battery as described below, the anode is separated from the cathode by a ceramic separator and further as soon as possible after the electrochemical cell has reached operating temperature and during subsequent operation of the cell. It is preferable to have a ceramic surface that is in sufficient contact with the anode and the alkali metal to make contact.

Therefore, it is desirable to use doping transition metal oxides that are electrochemically inert in the intended cell anode environment and are also reasonably priced.

For these reasons, cells of the type in question have a fused sodium anode and beta-alumina or nasico.
Considering having a solid electrolyte that is n), the method may be applied to a solid electrolyte that is a member of a group that includes beta-alumina containing sodium ions and a Nasicon ceramic solid conductor, where the doping is iron, It is performed with an oxide of a single transition metal selected from the group comprising nickel, copper, manganese, cobalt, chrome and molybdenum.

The Applicant has found that oxides of iron, nickel, copper, manganese and chromium are electrochemically inert in the anodic environment of cells of this type and are readily available at acceptable prices. .

The Applicant is not fully aware, in the present invention, of the exact mechanism by which the transition metal oxides are doped on the ceramic surface by molten alkali metal to improve the wettability of said surface. According to one aspect and without being bound by theory, transition oxide molecules, clusters or crystallites of the molecules, for example molecules of ferric oxide or nickel oxide, are absorbed, ie on the ceramic surface. It may be considered that they can be absorbed and / or adsorbed at active sites that are distant from each other. The doping of the ceramic surface with the transition metal oxides therefore does not necessarily have to be used for providing a coating or a continuous surface layer on the surface of said oxide. When excessive oxide doping is carried out, for example, to provide a continuous layer or coating of this kind, the oxide only sticks more or less permanently to said active sites, making available active adsorption on the ceramic surface. The remainder of the oxide layer or coating in excess of that absorbed at the site is in the form of a dry, loose powder, without reliable functional properties for possible wetting of the ceramic surface. Excessive oxides of this kind are not necessarily harmful, but are considered to be useless at best, since they do not adversely affect the wetting or electrochemical operation of the cell.

Alternatively, in some cases, depending on the transition metal selected, the transition metal oxide may be integrated or incorporated into one of the ceramic crystal textures or lattices at mutually spaced active sites on the ceramic surface. To form a part. The oxides may be present in the form of mixed oxides, either by themselves being incorporated as transition metal oxides or mixed with oxides of alkali metals which are ionically conductive, for example via ceramics.

However, whatever the mechanism, an increase in wetting was observed.

Transition metal oxides are doped by absorption at active sites on the ceramic surface, as is believed to be the case, for example, for ferric oxide, nickel oxide or cupric oxide on beta-alumina. The transition metal oxide can be reduced by the molten alkali metal to wet the ceramic surface. Accordingly, transition metal oxides are used in electrochemical cells of the type described above and are reduced to the transition metal itself, such as iron, nickel or copper, on a beta-alumina ceramic surface, crystallites, atoms or atoms of the transition metal. It remains absorbed in the form of atomic clusters. However, the Applicant has found that, even after such reduction, the wettability of the ceramic surface with the alkali metal in question practically holds an improvement. This is because it is clear that wetting can be practically easier in the presence of both the transition metal oxide and the transition metal after reduction with alkali metal than in the undoped ceramic surface.

As is believed to be possible in the case of manganese oxide or chromium oxide, where transition metal oxides are integrated with the crystal planes, either on their own or in the form of oxides mixed with alkali metal oxides. In some cases, the Applicant has found that the transition metal oxides are not reduced by contact with alkali metals and instead, to some extent and without limitation, remain in the form of oxides on the ceramic surface, improving wetting. I found that.

The applicant has found the following. That is, a suitable method of doping the ceramic surface with the transition metal oxide of interest is to wet the coating with a coating of a solution of the transition metal salt in a solvent solution, dry the surface, and leave the surface to leave a deposit of salt on the surface. To evaporate the solvent and further convert the deposited salt to a transition metal oxide.

Therefore, easy or at least sufficient solubility in a suitable solvent solution to provide a solution of a sufficient concentration of the transition metal salt is a criterion for the selection of the transition metal salt in question and then, after drying, is properly enhanced. Sufficient salt deposition is left on the ceramic surface in order to achieve a sufficient number of active site dopings on the surface to provide the desired wetting. Preferably the salt is soluble enough to provide a sufficiently high concentration of solution to dope virtually all said active sites, ie all potential absorption sites.

Water may usually be used as the solvent. However, in some cases, the Applicant has encountered difficulties in drying the ceramic surface with water and / or converting the deposited salts into oxides. However, in order to improve the solubility of the transition metal salts, it is preferred to use polar solvents, for example having a hydroxyl group, and such solvents are also due to their low viscosity and / or high surface tension, the ceramic surface. Should be easily moistened. In this regard, the Applicant has discovered that short-chain monohydric alcohols are suitable when the difficulties mentioned above are met with the preferred water solvent. This is because these alcohols readily wet the ceramic surface, while the appropriate salts of some commonly encountered transition metal oxides are ideally soluble in it, and this type of alcohol is also readily wetted from the wet surface during drying. It evaporates leaving no residue which interferes with the conversion of the deposited salts of the transition metals into oxides. In addition, this type of alcohol has a high evaporative property that facilitates easy and rapid evaporation from the ceramic surface, and its low viscosity leads to a quick and easy evacuation from the wet ceramic surface, which results in a continuous uniform film of the desired solution film. Results in a thin surface attachment.

Therefore, the solvent can be selected from the group comprising water, methanol, ethanol, and n-propanol. When short chain alcohols of this kind are used, they may be used in the form of a mixture but must be anhydrous.

Water is generally the preferred solvent, but in some cases,
It has been found to be a poor solvent compared to short chain alcohols such as ethanol. In the case of water, if there is not enough contact time between the solution and the surface so that the transition metal salt will be sufficiently adsorbed between the surface and the surface, it will be discharged quickly from the ceramic surface leaving a damp spot. Will be done.
This is why anhydrous alcohol is sometimes used.

Solvents of this type are readily available at an acceptable cost and can be used to consider the choice of transition metal salt. Thus, transition metal salts can be conveniently used to determine which are water-soluble or short-chain alcohol-soluble and which are strongly absorbed at the active site on the ceramic surface. However, normally the alcohol is used only if it is known that water is not suitable.

To wet the ceramic surface with the solution, either by dipping or
Alternatively, it may be applied or sprayed, and evaporation of the solvent may be carried out in the air or by heating to a suitable high temperature as described above.

Applicants have dried the alcohol-based halide solution at 30-50 ° C and the aqueous nitric acid solution at 150 ° C.

In principle, as indicated above, any transition metal salt can be used for the process according to the invention, but during the conversion into transition metal oxides of gases which can harm the ceramic surface from an electrochemical point of view. It is preferred to use salts that do not provide any such product. Halide inorganic salts such as chlorides or nitrates have been found to be suitable in this respect. In addition, nitrates are typically highly acidic and oxidative, making them easy to coat even after exposing the beta-alumina tubing to ambient air, and readily available, highly water soluble, and easily Decomposes into oxide.

The operation of converting the deposited salt to the oxide also includes the operation of heating the dried ceramic to a high temperature. Therefore, if the salt is a halide, the heating may be carried out in an oxygen-containing oxidizing atmosphere such as air, which will cause the halide to oxidize when heated to a sufficient temperature for a sufficient time. Convert to things. Further, when the transition metal halide is heated in air, and if the air contains sufficient moisture, conversion to the oxide is 150-250 ° C, eg 2 ° C.
Hydrolyze the halide to a gaseous acid and a hydroxide of the transition metal over a period of 15-45 minutes, such as 30 minutes, at a relatively low temperature such as 00 ° C. and then convert the hydroxide to an oxide. It can be carried out. Dry air may require heating at different temperatures for different periods of time. The Applicant has likewise found that heating at a similar temperature, for example 200 ° C., in an oxidizing atmosphere such as air in the case of nitrates decomposes to the oxides.

However, if the salt is, for example, one nitrate, it will automatically decompose into oxides on heating and need not be carried out in an oxygen-containing oxidizing atmosphere, but for convenience the heating will be like air. An oxidizing atmosphere is used.

The Applicant has succeeded in using ferric chloride, nickel chloride and manganese nitrate to produce a wettable beta alumina with sodium. Thus the salt may be a compound of a transition metal and an anion selected from the group comprising halide and nitrate anions.

On the other hand, as mentioned above, it is necessary to have the transition metal salt dissolved in the solvent at a concentration such that the metal ions in the dissolved salt are sufficient to occupy all potential absorption sites on the ceramic surface. However, the concentration should not be so high as to remove water from the atmosphere. In the case of ferric chloride, this can be done when the solution concentration is higher than 20% by weight, so that 10-20% by weight of ferric chloride is obtained.
Is preferred.

If the absorbing oxide is a transition element, such as iron, nickel or copper, which is reduced to the metal by contact with the molten alkali metal, the doped oxide can be natural if desired, for example in a hydrogen atmosphere in a furnace. However, separate reduction is usually not necessary, since contact with alkali metals in the high temperature electrochemical cell environment immediately reduces oxides of this type in any case.

Especially in the case of transition metals such as manganese or chrome,
The oxide is combined with the crystal structure of the ceramic and the doping of the ceramic surface wets this surface with a suspension of the transition metal oxide in a liquid, dries the surface and leaves an oxide layer on the surface. This includes evaporating the suspension and heating the dry surface to dope the oxide.
In the case of transition metal oxides, they form part of mixed oxides, which are mixed with alkali metal oxides whose ions are conducted through the ceramic.

For such suspensions, water is preferred as the liquid.

The invention further comprises a molten alkali metal anode, a cathode, and a separator, which is a ceramic solid electrolyte conductor containing anode alkali metal ions between the anode and the cathode and spaced apart from each other. Further to the high temperature electrochemical storage cell, said separator has a surface in contact with the molten alkali metal of the anode, the surface being made for wetting by the above method with the alkali metal of the anode.

The invention will now be described with reference to the following examples, which are non-limiting examples,
Further, description will be given with reference to the accompanying drawings showing a schematic side cross section of the cell of the present invention.

In the figure, the cell of the present invention is generally designated by the numeral 10. The cell 10 includes a tubular steel jacket 12 in which is concentrically arranged a beta-alumina tube 14 having one end closed and the other end open. In the figure, the cell is shown standing with the closed end of the tube 14 down and the open end up. The open end is sealed by glass to an alpha-alumina ring 16, against which the jacket 12 is also sealed with glass to provide a closed anode compartment between the tube 14 and the jacket 12. .

The upper end of the pipe 14 is closed by a tubular steel closing member 18, and a rod-shaped or rod-shaped steel current collector 2 is provided at its center opening.
0 is sealed and extends concentrically downward in the tube 14 to a position close to the closed end of the tube.

The jacket 12 extends upwardly over the outer curved surface of the ring 16 and then bends to the upper surface of the ring 16 to form the rim 21.
To form. The steel anode terminal post 22 is fixed to the floor surface of the rim 21, and the steel cathode terminal 24 is fixed to the closing member 18.

The tubular cathode structure 26 is shown in the annular space between the current collector 20 and the inner surface of the tube 14. In the example shown,
This cathode structure is a stoichiometrically accurate porous iron matrix impregnated with molten salt electrolyte of NaAlCl ₄ , which contains solid NaCl dispersed in particulate form and has a charged state. Then, it contains dispersed FeCl ₂ . (Alternatively, if desired, sulfur / sodium polysulfide cathode 26
Can also be used). Anode compartment tube 14 and jacket 12
In between, a low level of molten sodium anode material 28 is filled and a glass space 30 under vacuum is filled with sodium 2
Exists on 8 levels.

The outer surface 32 of the tube 14 is tightly wrapped with an iron or nickel mesh screen 34, which acts as a wick to wick molten sodium anode material over as wide an area of the surface 32 as possible. This waking is done by capillary action due to gravity on the level of sodium 28. The outer surface 32 is initially doped with, for example, ferric dioxide according to the method of the present invention, which is reduced to iron prior to loading into the cell (see Example 2) by contact with molten sodium in the cell. (See Example 1). This doping substantially improves the wettability of the surface 32 and facilitates waking with the shield 34 despite changes in sodium level caused by the normal charge / discharge cycle of the cell.

Example 1 A beta alumina tube separator for a high temperature electrochemical cell,
In accordance with the method of the present invention, the starting tubes are immersed in a 15% by weight solution of ferric chloride in absolute ethanol, the excess solution is drained off, then they are immediately introduced into air heated to 40 ° C. It was prepared by evaporating the solvent, leaving an adsorption layer of ferric chloride. Immediately after drying, that is, after a few seconds or minutes, it is introduced into air heated to 200 ° C.
Hold for 0 minutes to hydrolyze ferric chloride to ferric hydroxide and convert this hydroxide to ferric dioxide. The tubes were then immersed in molten sodium at 250 ° C. for immersion testing. Both conventional and non-treated lead acetate surface treated specimens with improved wettability were tested. The tubes made according to the invention are easily wetted with molten sodium and easily form a continuous layer on them, whereas the tubes of the specimen cannot be wetted with molten sodium at this low temperature and It was The ferric dioxide was reduced to iron by contact with molten sodium, while the doped iron persisted on the tube which retained the enhanced wettability.

Example 2 Example 1 was repeated. However, after heating in air at 200 ° C. for 30 minutes, the tube was introduced into a hydrogen furnace to reduce the adsorbed ferric oxide surface layer (which gives the tube a reddish color) to adsorbed metallic iron. These tubes are the same as the tubes of the present invention of Example 1 25
It was found to wet easily in molten sodium at 0 ° C.

Further tests to determine the effectiveness of the dopant,
It was carried out using an experimental cell operating in the temperature range of 175 ° to 420 ° C.

Each of these cells is slightly different from the one shown, each being an external sodium electrode that is pressed and covered with a mild steel jacket, and a beta-alumina tube sealingly glassed to an alpha-alumina insulating collar. A central aluminum column inside the beta-alumina tube. The device was insulated with a collar to electrically insulate the central column from the cell envelope. The beta alumina tube was electrolytically filled to the standard height with sodium. From the beta-alumina tube dimensions, the sodium height in the tube, and the beta-alumina resistance, the theoretical resistance of the beta-alumina tube can be calculated. The actual resistance of a cell can be empirically determined by passing a known current through the cell and measuring the voltage drop across the cell. The resistance of the metal part of the cell is determined by the resistance of the cell minus the resistance of the metal part resulting in the value of the beta-alumina tube resistance under test. If the tube is completely wetted with liquid sodium, the calculated and measured tube resistance should be the same.

The ratio of the calculated resistance to the experimental value shows the effect of the coating, ie the lower the measured resistance the better the surface is wetted by sodium.

The beta-alumina tube is virtually identical, made from a starting material containing 70% by weight boehmite and 30% by weight alfa-alumina, to which soda and lithium oxide dopants have been added, so that the soda is 9.1% of the doped material.
%, And lithium oxide also occupies 0.7% by mass. This material was slurried in water, spray dried, isostatically pressed into a tube and fired to obtain individual beta alimina.

Example 3 A beta-alumina tube was assembled undoped to sample two sodium / sodium cells as described above.

Four sodium / sodium cells were assembled by doping a beta alumina tube with manganese oxide.

A 50% strength by weight aqueous solution of manganese nitrate was applied to the outside of each tube with a brush, then the solution was poured inside the tube and then deposited by emptying it. The tube was then placed in an oven at approximately 180 ° C to decompose the nitrate into manganese oxide.

The resistance of the Na / Na cell was measured at 262 ° C.

Clearly the Na / Na cell resistance was low in the doped tube. In this example, the doping is such that the wetting of beta-alumina by molten sodium is such that the value of the ratio is approximately a factor of 2.
Improved to prove that it has increased by a factor of two. Therefore, the effect of doping by contact with molten sodium of a transition element oxide forming a mixed oxide with sodium oxide will be shown. This good wetting occurs at relatively low temperatures of 262 ° C.

Example 4 An additional four sodium / sodium test cells were assembled to test iron oxide doped beta-alumina tubes.

A 15 wt% ferric chloride solution in absolute ethanol was applied to the tube both by brushing and dipping. Then 40
The alcohol solvent was evaporated by heating in air to 0 ° C, leaving a layer of adsorbed ferric chloride on it. During drying, the tube was heated to 200 ° C. in air and kept at this temperature for 30 minutes to hydrolyze the ferric chloride to ferric hydroxide and to convert the hydroxide to ferric dioxide.

Two more cells were used as samples, and the beta alumina tube was assembled without doping. Various sodium /
The resistance value of the sodium cell was measured at 262 ° C.

In this example, doping with the transition element oxide, which is reduced to the metal upon contact with sodium, improved the wettability of beta-alumina as evidenced by the increase in the ratio at 260 ° C of approximately 30%. No specific difference was noticed depending on whether the doping was by brushing or dipping.

Example 5 Two more sodium / sodium test cells were assembled to test chromium oxide tubes.

The tube was doped by making a saturated aqueous solution of sodium dichromate, coating it on the tube and drying in air at 120 ° C.

The resistance value of the cell was measured at 274 ° C.

In this example, the mixed sodium / chromium oxide doping also lowers the resistance of the sodium / sodium cell at the relatively low temperature of 274 ° C., similarly indicating that sodium improves the wetting of the beta-alumina tube. Was done.

Example 6 Two more sodium / sodium test cells were assembled to test the doping of beta-alumina tubes. A saturated aqueous solution of sodium molybdate (NaMoO ₄ ) was applied to the tube by brushing.

The resistance measurements of these cells were compared to cells with undoped tubes.

The use of mixed sodium / molybdenum oxide has been shown to reduce cell resistance and improve sodium wetting by 24%.

Example 7 Two more sodium / sodium test cells were assembled with tubes doped with copper oxide and chromium oxide. A 25% by mass aqueous solution of hexavalent chromium oxide and an equal amount mixed solution of a 50% by mass aqueous solution of copper nitrate were prepared. The finished solution was applied to the outside of the tube and the inside of the tube was applied by injecting the solution into the tube and then emptying the tube. The solution was found to stick to beta-alumina tubes.

The resistance measurements of these cells were compared at 280 ° C. with the resistance measurements of the undoped sample cells.

This example demonstrates that a dopant is used which contains an oxide containing two transition elements, one of which (chromium) is the transition element forming a sodium / chromium mixed oxide. Here again there is an increase in the wetting of beta-alumina by sodium.

The present invention is of the type in which a molten sodium anode is separated from a sodium aluminum chloride molten salt electrolyte in which a porous cathode structure containing ferrous chloride as the active cathode material is immersed through a beta-alumina separator.
It is believed to be particularly effective in constructing a high temperature secondary electrochemical cell. Cells of this type usually have an operating temperature of approximately 250 ° C., and still higher temperatures of 350-400 ° C. destroy their cathode structure.

The invention is also applicable to sodium sulphide cells equipped with beta-alumina separators, but since cells of this type have operating temperatures of 250 ° C. and above, wetting is less of an issue.

In particular, the present invention has many advantages over the use of lead acetate, which is commonly applied to beta-alumina surfaces to promote sodium wetting. The lead acetate coated tube is heated to 350-400 ° C. to decompose the lead acetate into lead, which promotes wetting by molten sodium at these temperatures. However, when the temperature drops to 250 ° C, dewetting of lead acetate treated tubes can occur as a result of the dissolution of lead in sodium at still higher temperatures of 350-400 ° C. Further, as mentioned above, temperatures of 350 to 400 ° C. can adversely affect ferric chloride cathodes of the type described above.

In fact, a cell of the above type constructed of tubes made according to Examples 1 and 2 above worked well, with no increase in the internal resistance of the cell cycle due to incomplete wetting of the tube with the molten sodium anode. . In contrast, similar cells with untreated tubes show an increase in the internal resistance of the cycle due to dewetting, which can only be reversed by heating these sample cells to 400 ° C. It works against you. The good wetting of the cell of the present invention also applies to the internal anodic cell where sodium is in contact with the extremely smooth beta-alumina surface inside the tube formed by pressing the tube being manufactured against a smooth stainless steel mandrel. It has been found. These surfaces are usually very difficult to wet with sodium because of their smoothness.

[Brief description of drawings]

The figure is a schematic side sectional view of the cell of the present invention. 10 ... Cell, 12 ... Envelope, 14 ... Beta-alumina tube, 1
6 ... Alpha alumina ring, 18 ... Closing member, 20 ...
Current collector, 22 ... Anode terminal column, 24 ... Cathode terminal column, 26
... tubular cathode structure, 28 ... sodium melt, 34 ... metal mesh shield.

Claims (12)

[Claims] 1. A method for producing a surface of a ceramic solid electrolyte conductor containing alkali metal ions by means of a molten alkali metal whose ions are conducted through the ceramic so as to improve the wettability of said surface. Wet the ceramic surface with a solution of a transition metal salt liquid solvent,
Immobilizing transition metal oxides on the surface by drying the surface and evaporating the solvent to leave a salt deposit on the surface, converting the deposited salt to a transition metal oxide. A method for producing a surface of a solid electrolyte conductor containing. 2. The solid electrolyte is a member of a group comprising the Nasicon ceramic solid electrolyte conductor of beta-alumina and sodium, and the transition metal oxide is iron, nickel,
The method according to claim 1, which is an oxide of a single transition metal selected from the group including copper, manganese, cobalt, chromium and molybdenum. 3. The solution is water, methanol, ethanol and n.
The method according to claim 1, which is a solution of a salt in a solvent selected from the group containing propanol. 4. The method of claim 1 wherein converting the deposited salt to an oxide comprises heating the dried ceramic at an elevated temperature.
Item 5. The method for producing according to Item 3 or Item 3. 5. The manufacturing method according to claim 4, wherein the heating is performed in an oxygen-containing oxidizing atmosphere. 6. A process according to any one of claims 3 to 5 wherein the salt is a transition metal compound having an anion selected from the group comprising halide and nitrate anions. Method. 7. A method for producing a surface of a ceramic solid electrolyte conductor containing alkali metal ions by means of a molten alkali metal whose ions are conducted through the ceramic so as to improve the wettability of said surface. And
By wetting the ceramic surface with a suspension of a transition metal oxide, drying the surface and evaporating the suspension to leave an oxide deposit on the surface and heating the dried surface. A method for producing a solid electrolyte conductor, which comprises fixing the oxide to the surface. 8. A group wherein the solid electrolyte is a member of a group containing a beta-alumina and a Nasicon ceramic solid electrolyte conductor of sodium ions, and the transition metal oxide is a group containing iron, nickel, copper, manganese, cobalt, chromium and molybdenum. The method according to claim 7, wherein the oxide is a single transition metal oxide selected from the group consisting of: 9. A process according to claim 7 in which the transition metal oxide forms part of a mixed oxide and is mixed with an oxide of an alkali metal whose ions are conducted through the ceramic. Method. 10. The suspension comprises methanol, ethanol, n
8. A process according to claim 7 which is selected from propanol and mixtures thereof and is anhydrous. 11. A ceramic solid electrolyte comprising an alkali metal ion having a surface on which a deposit of a transition metal oxide is provided to improve wettability by the molten alkali metal to which the ion is conducted. Conductor. 12. A high temperature electrochemistry having a molten alkali metal anode, a cathode, and a separator, which is a ceramic solid electrolyte conductor containing anode alkali metal ions, between the anode and the cathode and separating them from each other. In the electricity storage cell, the separator has a surface in contact with the molten anode metal of the anode, and the surface is formed by the molten alkali metal of the anode.
A ceramic solid electrolyte conductor having thereon a deposit of oxide of a transition metal to improve its wettability.